Method for reel changing in automatic machines

ABSTRACT

A method for reel changing in automatic machines including: preparing a carriage having a robotic arm including a gripped with a gripper at its free end for retaining a reel; the carriage has a support for the reel and a container for collecting cores of empty reels; positioning the reel on the support defining a predetermined position and memorised by the arm; moving the carriage forward toward a rotating shaft in a position allowing movement of the arm towards the shaft; reading a code on the shaft by a reading device on the arm; sending a signal by the reading device corresponding to the reading of the code to a processing unit with memorisation of the position of the shaft; picking up of an empty core from the rotating shaft and releasing the core in the container; picking up the reel; inserting the reel in the rotating shaft.

TECHNICAL FIELD

This invention relates to a method for reel changing in automatic machines. In particular, the method is used for the changing of reels in automatic machines used for making filter bags containing infusion products (such as tea, coffee, camomile or the like).

BACKGROUND ART

It is known that the automatic machines for making filter bags are provided with a plurality of reels for feeding various types of material necessary for forming filter bags. Each reel is supported by a corresponding motor-driven shaft protruding from a wall of the machine frame.

In particular, each automatic machine is basically provided with at least one reel of filter paper (in some cases also two reels, of which one is for direct feeding and the other as reserve in the case of emptying the first reel) and a reel with strips of labels on which is added, in the case of packages with this option, also a reel of strips of material for wrapping the filter bags formed.

It should be considered that:

-   -   each automatic machine uses a large number of reels;     -   each reel has, individually, a considerable weight;     -   each automatic machine has a high production speed and it is         therefore necessary to constantly change empty reels with new         reels with a very high frequency.

The changing of reels is currently performed manually by a machine operator who proceeds as follows:

-   -   the operator is alerted that the reel of the automatic machine         is empty;     -   the core of the empty reel is removed from the shaft of the         automatic machine;     -   a corresponding type of new reel to be replaced is picked up         from a general storage unit or from an auxiliary storage unit;     -   the new reel is coupled on the shaft of the automatic machine.

However, the replacement process has several drawbacks:

-   -   high costs, since an operator must be present at each automatic         machine for constant monitoring of the machine in view of the         large number of types of reels to be replaced together with the         high operating speed of the machine;     -   large physical effort by the operator for carrying reels from         the storage unit to the automatic machine at each replacing         request;     -   possible risk of a machine stoppage if an operator is         responsible for several machines (which are also not close to         each other) and the two machines have a simultaneously request         for changing the reel.     -   risk of error in the loading of the type of material in the         reel.

DISCLOSURE OF THE INVENTION

The aim of the invention is to provide a method for reel changing in automatic machines which overcomes the above-mentioned drawbacks and which can be extended in a simple manner to all the types of automatic machines of this technological sector.

In particular, the aim of the invention is to provide a method for reel changing in automatic machines which is able to automate and speed up the reel changing process without the intervention of an operator.

A further aim of the invention is to provide a method for reel changing in automatic machines which is able to always ensure the correct reel changing as a function of the requirements of the machine with reduced response times.

Said aims are fully achieved by the method for reel changing in automatic machines according to the invention as characterised in the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

The features of the invention will become more apparent from the following detailed description of a preferred, non-limiting embodiment of it, illustrated by way of example in the accompanying drawings, in which:

FIG. 1 illustrates a schematic top plan view of an automatic machine for making filter bags for infusion products and a carriage for implementing the reel changing method in automatic machines, according to the invention;

FIG. 2 illustrates a schematic side view of a carriage with a robotic arm of FIG. 1;

FIGS. 3A to 3F illustrate schematic side views of a corresponding series of steps forming the reel changing method in automatic machines, according to the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

With reference to the accompanying drawings and with particular reference to FIG. 1, the reel changing method according to the invention is used for automatic machines, denoted in its entirety by the numeral 1, used for making filter bags containing infusion products (such as tea, coffee, camomile and the like).

The automatic machine 1 comprises at least, on a machine front (that is, on a front vertical wall of a machine frame supporting the operating stations), a rotating shaft 2 for receiving at least one reel 3 of wound material, preferably of the filter paper type for forming filter bags for infusion products.

The rotating shaft 2 has a first identification code C1 (for example a position marker preferably of the type formed by a Charuco code).

As illustrated, the method for changing the reel 3 comprises the following steps:

-   -   preparing a mobile carriage 4 having a robotic arm 5 equipped         with a gripper 6 at its free end configured at least for         retaining a reel 3 (FIG. 3A), which is not empty, which will be         referred to as full; the mobile carriage 4 having a support 7         for the full reel 3 and a container 8 for collecting cores 9 of         empty reels; the support 7 for the reel 3 and the container 8         are integral and mobile with the mobile carriage 4;     -   preparing a unit 12 for control, memorising and processing data         and related at least to the position of the robotic arm 5 and of         the mobile carriage 4; positioning the full reel 3 on the         support 7 of the carriage 4 defining a position which is         predetermined and memorised by the control unit 12 (FIG. 3A);     -   moving the carriage 4 for moving the carriage 4 towards the         front of the machine 1 in a first zone Z1 predetermined and         memorised by control and data processing unit 12 in the         proximity of the at least one rotating shaft 2 and in a position         configured for allowing the movement of the robotic arm 5         towards the rotating shaft 2 (FIG. 3A);     -   reading the first identification code C1 present on the rotating         shaft 2 by a reading device 10 positioned on the robotic arm 5;     -   sending a signal by the reading device 10 corresponding to the         reading of the first identification code C1 to the control and         data processing unit 12 positioned on the carriage 4 for the         memorisation of the position of the rotating shaft 2 (FIG. 3B);     -   picking up a core 9 of an empty reel from the rotating shaft 2         by the robotic arm 5 using the gripper 6 and releasing the core         9 of an empty reel inside the container 8 present on the         carriage 4 (FIGS. 3C-3D);     -   picking up the full reel 3 positioned on the support 7 of the         carriage 4 by the gripper 6 of the robotic arm 5 (FIG. 3E);     -   inserting the full reel 3, picked up from the support 7, in the         rotating shaft 2 of the machine 1.

As mentioned above, the first identification code C1 may be a position marker preferably of the type formed by a Charuco code including the data necessary for the robotic arm 5.

In this description reference will be made to a single rotating shaft 2 and a single type of reel 3, merely by way of example and without limiting the scope of the invention, but the method can be used for all the other reels used on this type of automatic machine, such as, for example, reels of strips of labels or reels of strips of wrapping paper supported by corresponding shafts located on the machine and which form part of the complete formation of a filter bag.

The method actuated in this way makes it possible to create a synergy between a mobile carriage equipped with reading and memorising systems of the operating zones (as described in more detail below), a fixed support for the reel with a robotic arm configured for the gripping, positioning and releasing operations both of the reels and of the cores on the command of the control and processing unit 12 positioned on the carriage 4.

Advantageously, the carriage is provided both with the reel support and a container for the empty cores so as to form, together with the robotic arm, an independent mobile work island around the machine without the need for intervention by operators during a long working period.

Preferably, the method also comprises the following steps, prior to the step of positioning the full reel 3 on the support 7 of the carriage 4 (FIGS. 1 and 2):

-   -   preparing at least one magazine 11 of full of reels 3; the         magazine 11 is provided with a second identification code C2         having as data at least the position of the reel 3 relative to         the magazine 11;     -   moving the carriage 4 towards the magazine 11 of full reels 3 in         a position configured for allowing the approach of the robotic         arm 5 both to the second identification code C2 and to the full         reel 3;     -   reading the second identification code C2 by the reading device         10 positioned on the robotic arm 5;     -   sending a signal corresponding to the reading of the second         identification code C2 to the control and data processing unit         12 positioned on the carriage 4 for memorising and confirming         the data;     -   positioning and picking up the full reel 3 from the magazine 11         by the robotic arm 5 by engaging the gripper 6 in the core 9 of         the full reel 3 to be picked up;     -   positioning and releasing of the full reel 3 on the support 7 of         the carriage 4.

Preferably, the reading step of the device 10 also detects on the second identification code C2 the correct type of magazine 11 relative to the type of reel 3 to be picked up.

It should be noted that in the presence of several magazines having corresponding different types of reels housed therein, the code C2 must comprise an identification marker of the type of reels stored therein.

In this way, the combination of the carriage, robotic arm and reels magazine in a reduced space allows a greater speed of execution and a greater flexibility and operating independence of the reel changing system as a whole.

Preferably, the second identification code C2 can comprise, as memorised data, the type of reel 3.

In light of this, the steps for moving the carriage 4 take place in a delimited and predetermined operating area A, above a treadable surface PC, around the automatic machine 1 in which are positioned at least two zones Z1, Z2 memorised by a unit 12 for controlling the carriage 4 corresponding to the zone Z1 in front of the at least one shaft 2 of the machine 1 and a zone Z2 for waiting for or reloading the carriage 4 with a full reel 3.

Preferably, the step of picking up the core 9 of the empty reel from the rotating shaft 2 by the robotic arm 5 using the gripper 6, is obtained by the direct gripping of the core 9 by the gripper 6.

In some particular cases, the picking up step may be preceded by a pre-withdrawal step of the empty core 9 again by means of the gripper 6 acting on the rotating shaft 2.

It should be noted that the pre-withdrawal step is achieved by means of a movement of the core 9 in a direction parallel to the axis of extension of the rotating shaft 2 in such a way as to allow a portion of core 9 to protrude from the rotating shaft 2.

Preferably, the steps of moving the carriage 4 take place in a delimited operating area A also having a further zone Z3 memorised on a side of the magazine 11 of full of reels.

The zone Z3 may also coincide with the zone Z2 for waiting for or reloading the carriage 4 with a full reel 3.

It should be noted that the steps of reading the data reading device 10 are obtained with a camera 10 a positioned on the robotic arm 5.

The camera 10 a is connected to a unit 10 b for controlling and sending data to the data control and processing unit 12 located on the carriage 4.

Preferably, the control unit 10 b is located on the carriage 4.

More specifically, the control unit 12 is designed for operation of the carriage 4 and the movements of the robotic arm 5 thanks to the processing and memorisation of the preset data and the data arriving from the reading device 10.

In light of this, the unit 12 for controlling, memorising and processing data is positioned or housed in the mobile carriage 4.

Preferably, the step of positioning and picking up the full reel 3 from the magazine 11 by the robotic arm 5 is also obtained with the aid of a laser emitter 10 c positioned on the robotic arm 5.

Preferably, the laser emitter 10 c is independent from the camera 10 a and is connected directly to the control and processing unit 12.

Alternatively, the laser emitter 10 c may be included in the reading device 10 with a relative connection to the control unit 10 b.

According to a further embodiment, the laser emitter 10 c may be included in the reading device 10, but the laser emitter 10 c is connected directly to the control and processing unit 12.

It should be noted that the step of positioning and picking up the full reel 3 from the magazine 11 by the robotic arm 5 occurs by means of a command of the unit 12 which allows the robotic arm 5 to be positioned close to (in front of) the reel 3.

During a subsequent step, the laser reader 10 c is activated whilst the robotic arm 5 moves along a vertical axis, so that the laser beam can intercept an edge of the reel until reaching the core 9 of the reel 3.

With this movement of the robotic arm 5 the laser beam intercepts, in sequence, the reel edge, the core edge, the space, and, finally, the core edge again so as to allow the central unit 12 to calculate the diameter of the reel 3 and, subsequently, the centre of the reel 3.

At this point, the control unit 12 enables the movement of the robotic arm 5 which, thanks to the gripper 6, can correctly pick up the reel by the insertion in the core 9.

In addition, there can be a step for alerting the unit 12 by the laser emitter 10 c if the presence of the reel 3 in the position previously memorised is not determined by means of the marker on the magazine.

As mentioned above, the step of picking up the full reel 3 from the support 7 of the carriage 4 is performed by the robotic arm 5 without reading the position of the full reel 3. This is because this data is memorised by the unit 10 a of the robotic arm 5.

It should be noted that the steps for gripping and releasing the full reels 3 and the cores 9 of empty reels are obtained with a gripper 6 with two fingers radially movable towards and away from one another. In this way, the robotic arm 5 can penetrate in the cores 9 and adapt to the various diameters present.

Preferably, the method also comprises a step of replacing the gripper 6 on the robotic arm 5.

In light of this, the step for replacing gripper 6 is performed on board the carriage 4.

The carriage 4 is equipped with a container 13 of interchangeable grippers 6 positioned in a zone of the carriage 4 which can be reached by the robotic arm 5.

Preferably, the robotic arm 5 is of the anthropomorphic type with a large number of degrees of freedom (up to seven) which is able to operate with great flexibility.

Moreover, the carriage 4 has the control unit 12 which may be equipped with an optical sensor for detecting the zones Z1-Z3 of the operating area A or, alternatively, a geolocation system in which are memorised the positions of the zones Z1-Z3.

With a method structured in this way the preset aims are achieved thanks to the combined system between carriage with accessories, with the full reel support and container, and the robotic arm supported and movable with the carriage. In effect, the carriage allows the arm to quickly reach the working zones in which the robotic arm must operate.

In other words, a method has been developed using a “cobot” (or collaborative robot) combined with a mobile platform, thus optimising the use of a robotic platform for automatic machines, keeping the personnel safe and with the possibility of cooperation between personnel and “cobot”.

The system allows a greater level of positioning precision and increases the possible operations which the robotized arms can perform thanks also to a sufficiently robust and precise viewing system such that it can be used in an industrial environment.

As the robotic arm is able to memorise the relative positions of the reel support, machine shaft and the various positions of the magazines present, the times for gripping and releasing the reels can be speeded up, keeping the automatic machine operating safely and maximising its productivity.

The presence in the working area of reel magazines and grippers makes the reel changing method extremely safe and independent, and therefore with a reduced, if not zero, presence of control operators. 

1. A method for reel changing in automatic machines, the automatic machine comprising at least, on a machine front, a rotating shaft for supporting at least one reel of wound material; said shaft having a first identification code; wherein it comprises at least the following steps: preparing a mobile carriage having a robotic arm equipped with a gripper at its free end configured at least for retaining a reel; the mobile carriage having a support for the reel and a container for collecting cores of empty reels; the support for the reel and said container, being integral and mobile with the mobile carriage; preparing a control and data processing unit for control, storage and processing of data concerning at least the position of the robotic arm and the mobile carriage; positioning the reel on the support of the carriage defining a predetermined position and memorised by the control and data processing unit; moving the carriage for moving the carriage towards the front of the machine in a first zone predetermined and memorised by control and data processing unit in the proximity of the at least one rotating shaft and in a position configured for allowing the movement of the robotic arm towards the rotating shaft; reading the first identification code present on the rotating shaft by a reading device positioned on the robotic arm; sending a signal by the reading device corresponding to the reading of the first identification code to the control and data processing unit with memorisation of the position of the rotating shaft; picking up a core of an empty reel from the rotating shaft by the robotic arm using the gripper and releasing the core of an empty reel inside the container present on the carriage; picking up the reel positioned on the support of the carriage by the gripper of the robotic arm; inserting the reel, picked up from the support, in the rotating shaft of the machine.
 2. The method according to claim 1, comprising the following steps, prior to the step of positioning the reel on the support of the carriage: preparing at least one magazine of reels; the magazine being provided with a second identification code having as data at least the distance between the reel and the magazine; moving the carriage towards the magazine of reels in a position configured for allowing the approach of the robotic arm both to the second identification code and to the reel; reading the second identification code by the reading device positioned on the robotic arm; sending a signal corresponding to the reading of the second identification code to the control and data processing unit positioned on the carriage for memorising and confirming the data; positioning and picking up the reel from the magazine by the robotic arm by engaging the gripper, in the core of the reef to be picked up; positioning and releasing of the reel on the support of the carriage.
 3. The method according to claim 1, wherein the steps for moving the carriage take place in an operating area, above a treadable surface, predetermined around the automatic machine in which are positioned at least two zones (Z1, Z2) memorised by the control unit corresponding to the zone in front of the at least one rotating shaft of the machine and a zone for waiting for or reloading the carriage with a reel.
 4. The method according to claim 1, wherein the step of picking up a core of an empty reel from the rotating shaft by the robotic arm using the gripper is preceded by a step of pre-withdrawal of the core achieved by a manoeuvre of the robotic arm on the core.
 5. The method according to claim 2, wherein the steps of moving the carriage take place in a delimited operating area also having a further zone memorised on a side of the magazine of full reels.
 6. The method according to claim 1, wherein the steps of reading the reading device are achieved at least with one optical cell positioned on the robotic arm.
 7. The method according to claim 1, wherein the step of picking up the reel from the support by the robotic arm is performed without reading the position of the reel.
 8. The method according to claim 1, wherein the steps for gripping and releasing the full reels and the cores of empty reels are obtained with a gripper with two fingers radially movable towards and away from one another.
 9. The method according to claim 1, comprising a step of replacing the gripper on the robotic arm.
 10. The method according to claim 9, wherein the step of replacing the gripper on the robotic arm is performed on the carriage; said carriage being provided with a container of grippers.
 11. The method according to claim 1, wherein the unit for controlling, memorising and processing data is positioned or housed in the mobile carriage. 